Backhaul channel management for IAB networks

Abstract

A method for establishing a BH RLC channel between a node and a DU. The method includes a CU detecting (s 402 ) a need to establish the BH RLC channel between the node and the DU; and in response to detecting the need to establish the BH RLC channel, the CU sending (s 404 ) to the DU an AP message requesting the DU to setup the BH RLC channel. The AP message comprises: i) a list identifying one or more BH RLC channels to be setup, wherein the list comprises at least one item containing a BH RLC Channel identifier, ID, information element, IE, containing a BH RLC Channel ID identifying the BH RLC channel, or ii) a DRB ID IE containing the BH RLC Channel ID identifying the BH RLC channel.

The invention claimed is: 
     
       1. A method for establishing a backhaul (BH) radio link control (RLC) channel between a node and a distributed unit (DU), the method comprising:
 a central unit (CU) detecting a need to establish the BH RLC channel between the node and the DU; and 
 in response to detecting the need to establish the BH RLC channel, the CU sending to the DU an application protocol (AP) message requesting the DU to setup the BH RLC channel, wherein the AP message requesting the DU to setup the BH RLC channel comprises: 
 a list identifying one or more BH RLC channels to be setup, wherein the list comprises at least one item containing a BH RLC channel identifier (ID) information element (IE) containing a BH RLC channel ID identifying one of the one or more BH RLC channels to be setup. 
 
     
     
       2. The method of  claim 1 , wherein the at least one item included in the list further contains quality-of-service (QoS) information associated with the BH RLC channel. 
     
     
       3. The method of  claim 2 , wherein the QoS information comprises an allocation and retention priority (ARP) value. 
     
     
       4. The method of  claim 2 , wherein the at least one item included in the list further contains RLC mode information identifying an RLC mode to be used for the BH RLC channel. 
     
     
       5. The method of  claim 4 , further comprising:
 the DU, in response to receiving the AP message, determining whether the DU is capable of establishing the BH RLC channel; and 
 as a result of determining that the DU is capable of establishing the BH RLC channel, the DU establishing a DU side of the BH RLC channel. 
 
     
     
       6. The method of  claim 1 , wherein
 the AP message further comprises a downlink (DL) Packet Data Convergence Protocol (PDCP) sequence number (SN) length value, and 
 the method further comprises the DU ignoring the DL PDCP SN length value. 
 
     
     
       7. The method of  claim 1 , further comprising:
 the DU, in response to receiving the AP message, determining whether the DU is capable of establishing the BH RLC channel; and 
 as a result of determining that the DU is capable of establishing the BH RLC channel, the DU establishing a DU side of the BH RLC channel. 
 
     
     
       8. The method of  claim 7 , wherein establishing the DU side of the BH RLC channel comprises:
 allocating memory for an RLC buffer for the BH RLC channel; and/or 
 applying a BH RLC channel configuration indicated in the AP message. 
 
     
     
       9. The method of  claim 1 , wherein the AP message is an F1 AP (F1AP) message. 
     
     
       10. The method of  claim 9 , wherein the F1AP message is a UE Context Setup Request or a UE Context Modify Request. 
     
     
       11. A method for establishing a backhaul (BH) radio link control (RLC) channel between a node and a distributed unit (DU), the method comprising:
 the DU receiving an application protocol (AP) message transmitted by a central unit (CU), wherein the AP message comprises: 
 a list identifying one or more BH RLC channels to be setup, wherein the list comprises at least one item containing a BH RLC channel identifier (ID) information element (IE) containing a BH RLC channel ID identifying one of the one or more BH RLC channels to be setup. 
 
     
     
       12. The method of  claim 11 , wherein the at least one item included in the list further contains quality-of-service (QoS) information associated with the BH RLC channel. 
     
     
       13. The method of  claim 12 , wherein the QoS information comprises an allocation and retention priority (ARP) value. 
     
     
       14. The method of  claim 12 , wherein the at least one item included in the list further contains RLC mode information identifying an RLC mode to be used for the BH RLC channel. 
     
     
       15. The method of  claim 11 , wherein
 the AP message further comprises a downlink (DL) Packet Data Convergence Protocol (PDCP) sequence number (SN) length value, and 
 the method further comprises the DU ignoring the DL PDCP SN length value. 
 
     
     
       16. The method of  claim 11 , further comprising:
 the DU, in response to receiving an AP message, determining whether the DU is capable of establishing the BH RLC channel; and 
 as a result of determining that the DU is capable of establishing the BH RLC channel, the DU establishing a DU side of the BH RLC channel. 
 
     
     
       17. The method of  claim 16 , wherein establishing the DU side of the BH RLC channel comprises:
 allocating memory for an RLC buffer for the BH RLC channel; and/or 
 applying a BH RLC channel configuration indicated in the AP message. 
 
     
     
       18. The method of  claim 11 , wherein the AP message is an F1 AP (F1AP) message. 
     
     
       19. The method of  claim 18 , wherein the F1AP message is a UE Context Setup Request or a UE Context Modify Request. 
     
     
       20. A network function (NF) apparatus, the NF apparatus being adapted to:
 detect a need to establish a backhaul (BH) radio link control (RLC) channel; and 
 in response to detecting the need to establish the BH RLC channel, send an application protocol (AP) message to a distributed unit (DU), wherein the AP message comprises: 
 a list identifying one or more BH RLC channels to be setup, wherein the list comprises at least one item containing a BH RLC channel identifier (ID) information element (IE) containing a BH RLC channel ID identifying one of the one or more BH RLC channels to be setup. 
 
     
     
       21. The NF apparatus of  claim 20 , wherein the NF apparatus comprises a transmitter; and processing circuitry.